Microstructuring with femtosecond laser inside silica glasses

Summary form only given. Modification of the refractive index of transparent materials by UV laser radiation is widely used for writing waveguides and Bragg gratings in different type of glasses. Extending controlled writing to the inside of transparent materials is important since it opens a wide range of applications for integrated optical elements. In this work we report on direct writing of diffraction gratings and other optical elements inside different silica glasses with a train of femtosecond laser pulses at high repetition rate and study the influence of laser repetition rate and the number of pulses per focused area.